GROWTH COMPARISON BETWEEN WINTER AND SPRING SOWN VIRGINIA LONGLEAF PINE.

Philip Sheridan1,2, Leif Jacobson1, and Nancy Penick1

1.  Meadowview Biol. Research Station, Woodford, VA and
2.  Dept. of Biol. Sciences, ODU.
Longleaf pine, Pinus palustris Miller, is extremely rare in Virginia with only 4432 trees remaining.  Since no commercial supplier of Virginia longleaf pine was available we collected seeds from a natural stand on Union Camp property in the City of Suffolk, Virginia in November 1997.  Commercial propagation of longleaf pine in the southeast involves a May sowing with seedlings available for planting in the fall.  Our goal was to determine whether winter sown seed (n = 1748) would result in a significantly greater proportion of adequately sized seedlings (measured by root collar diameter) for planting versus spring sowings (n = 794).  We suspected that an earlier sowing might be necessary to offset the shorter growing season in Virginia.  Winter sown seeds were planted during December under 1/4 soil in greenhouse beds, seedlings transplanted to 14 oz. pots 1 month after germination, and pots placed in bottom-watered beds in May. Spring sown seeds were dewinged and sown topically two per pot in May. Winter-sown seeds received two Osmocote fertilizer applications while spring sown seedlings were fertilized once.  Root collar diameters were measured Jan.- Feb. 1999.  Winter sown seed resulted in a significantly greater proportion of seedlings with larger root collar diameter (> 5 mm) than spring sown seed.  We think that the small size of spring sown longleaf pine seedling root collar diameter can be overcome by both sowing in early March and more frequent fertilizer applications.